Effect Of Storage Ways On Quality Changes Of Small Packaging Rice

The effect of storage temperatures, packaging materials and ways of modified atmosphere packaging on small packaging rice quality during storage were studied in this paper. The relationship between the micro structural changes of rice endosperm was also studied to reveal the structure changes of rice quality. Through analyzing the experimental data of different modified atmosphere packaging, the changing trend of rice quality was obtained, and the reasonable way of modified atmosphere packaging was summarized. In addition, detailed experimental data base for small packaging rice preservation technology development was also provided in this paper.Firstly, quality changes of three different kinds of rice packaged with low-barrier property packaging materials CPP/PE during storage at 4℃, 25℃and 35℃were compared. Results showed that: the quality of rice still deteriorate even in short-term storage of 30 days at 4℃, but the rice stored at 25℃and 35℃, all the values showed significant difference between the original values in more than 30 days of storage. This indicated that natural packaging can't keep the rice quality not to change at low temperature during short-term storage. And the results also showed that although small packaging reduced the volume of packaging, the rice quality still deteriorated at normal temperature storage condition,.Secondly, the above rice were packaged with CPP/PE in four different modified atmosphere packaging ways (natural, filling with carbon dioxide, filling with nitrogen and vacuumizing storage) respectively, at accelerated storage conditions of 35℃and 60% relative humidity for 120 days(240 days at 25℃) . A comprehensive analysis of quality indexes measured periodically during storage was done, and the results showed that: vacuum packaging was the most effective way to delay the deterioration of rice quality during storage, which was suitable for long-term storage of small packaging rice. The experimental data also showed the chromatic aberrationa of rice which has a lower water content and higher fatty acid content changed a lot, with ratio of sticky and hardness decreased significantly. Though the price of CPP/PE was low, it can not meet the requirements of long-time storage, so it was not suitable for rice packaging.Thirdly, the quality changes of rice packed with high-barrier property packaging materials (PA/PE) storaged by the above four different modified atmosphere methods were studied respectively . According to comprehensive analysis of the quality changes, the results showed that packaging with carbon dioxide could effectively delay the speed of rice quality deterioration if storage time was more than 60 days. There was significant correlation between sensory evaluation and other indexes, the most effective indexes to evaluate rice quality were chromatic aberration (△E) and pasting enthalpy (△H).Finally, cross section′s microscopic structure of the rice, packaged with high-barrier property packaging materials and storaged for 120 days, was futher observed and analysis was conducted with combination of rice cooking indicators (rice bibulous rate, rice heating water absorption and rice inflation rate). The results showed that packaging with carbon dioxide could effectively keep the organizational structure and cooking properties of rice during long-time storage. The final results showed that small packaging rice with high-barrier packaging materials and packaging with carbon dioxide showed the best effect on delaying the aging of rice during accelerated storage for 180 days (9 months'storage time at 25℃).